Erectile dysfunction (ED) critically impacts quality of life in prostatectomy, diabetic and aging patients. The underlying mechanism involves cavernous nerve (CN) damage, resulting in ED in 80% of prostatectomy patients. Peptide amphiphile (PA) nanofiber hydrogel delivery of sonic hedgehog (SHH) protein to the injured CN, improves erectile function by 60% at 6 weeks after injury, by an unknown mechanism. We hypothesize that SHH is a regulator of neurite formation. SHH treatment promoted extensive neurite formation in uninjured and crushed CNs, and SHH inhibition decreased neurites >80%. Most abundant neurites were observed with continuous SHH PA treatment of crushed CNs. Once induced with SHH, neurites continued to grow. SHH rescued neurite formation when not given immediately. SHH is a critical regulator of neurite formation in peripheral neurons under uninjured and regenerative conditions, and SHH PA treatment at the time of injury/prostatectomy provides an exploitable avenue for intervention to prevent ED. Erectile dysfunction critically impacts quality of life in prostatectomy, diabetic and aging patients. The underlying mechanism involves cavernous nerve injury. As a step towards clinical translation, we examined how peptide amphiphile nanofiber hydrogels delivering sonic hedgehog protein to the cavernous nerve at the time of crush injury (rat prostatectomy model) significantly promote regeneration and improve erectile function. A key mechanism is sonic hedgehog regulation of neurite formation in penile projecting neurons, which is critical for re-innervation and clinical translation. Development of peptide amphiphile sonic hedgehog delivery has significant potential for high impact on future treatment of prostatectomy patients to prevent erectile dysfunction. Display omitted